US4519023A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-oscillating inverter including a DC to DC converter and method for control thereof
Assignee: Motorola Solutions Inc
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Filing: 1983-05-20
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Granted: 1985-05-21
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Expires: 2003-05-20
Abstract
Abstract A self oscillating inverter including a DC to DC converter and method for control thereof which senses the onset of a transformer core saturation to control its operation without dependence thereon. Linearizing inductors in the transformer secondary function to maintain a ramp shaped collector current waveform under full load conditions to allow control of output voltage by varying the oscillator frequency.
Inventors
- 👤 Theodore V. Lester
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:52
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/338; H02M3/3382; H02M3/3384
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
174 words
A control circuit for a one-transformer DC to AC inverter comprising: first and second switching means for alternately switching a current through a primary winding of said transformer connected to like first electrodes of said first and second switching means; means connected to common connected second electrodes of said first and second switching means for sensing a level of said current therethrough; means coupled to respective third electrodes of said first and second switching means for comparing said sensed current level to a reference level, said reference level corresponding to a current level just less than the primary current required for transformer saturation, and alternately deactivating and activating said first and second switching means each time said current level is substantially equal to said reference level wherein transformer saturation is prevented; and inductive loading means coupled to a secondary winding of said transformer for providing a generally linear ramp shaped increasing waveform to said current through said first and second switch means throughout the conduction time thereof, respectively, until said reference level is reached.
Claim 2
Dependent Claim
174 words
A control circuit for a one-transformer DC to AC inverter comprising: first and second switching means for alternately switching a current through a primary winding of said transformer connected to like first electrodes of said first and second switching means; means connected to common connected second electrodes of said first and second switching means for sensing a level of said current therethrough; means coupled to respective third electrodes of said first and second switching means for comparing said sensed current level to a reference level, said reference level corresponding to a current level just less than the primary current required for transformer saturation, and alternately deactivating and activating said first and second switching means each time said current level is substantially equal to said reference level wherein transformer saturation is prevented; and inductive loading means coupled to a secondary winding of said transformer for providing a generally linear ramp shaped increasing waveform to said current through said first and second switch means throughout the conduction time thereof, respectively, until said reference level is reached.
Claim 3
Dependent Claim
30 words
The control circuit of claim 1 wherein said first and second switching means comprise transistors and wherein said first, second and third electrodes are collector, emitter and base electrodes respectively.
Claim 4
Dependent Claim
31 words
The control circuit of claim 1 which includes means for coupling a feedback winding of said transformer to said first and second switching means for forming a self oscillating transformer circuit.
Claim 5
Dependent Claim
14 words
The control circuit of claim 1 wherein said sensing means comprises a sampling resistor.
Claim 6
Dependent Claim
79 words
The control circuit of claim 1 wherein said comparing means comprises a transistor and a pair of diodes, said diodes each having first like electrodes connected together and second like electrodes coupled, respectively, to control electrodes of said first and second switching means corresponding to said third electrodes of said first and second switching means, said transistor having a control electrode connected to said current sensing means and an output electrode connected to said common connected diode first electrodes.
Claim 7
Independent Claim
163 words
A method for controlling a DC to AC inverter comprising the steps of: alternately switching a current through a transformer primary winding by first and second switching means connected thereto at respective first electrodes thereof; sensing a level of current through said first and second switching means by means connected to common connected second electrodes thereof; comparing said sensed current level to a reference level by means coupled to respective third electrodes of said first and second switching means, said reference level corresponding to a current level just less than the primary current required for transformer saturation; alternately deactivating and activating said first and second switching means each time said current level is substantially equal to said reference level wherein transformer saturation is prevented; and inductively loading a secondary winding of said transformer for providing a generally linear ramp shaped increasing waveform to said current through said first and second switch means throughout the conduction thereof, respectively, until said reference level is reached.
Claim 8
Independent Claim
163 words
A method for controlling a DC to AC inverter comprising the steps of: alternately switching a current through a transformer primary winding by first and second switching means connected thereto at respective first electrodes thereof; sensing a level of current through said first and second switching means by means connected to common connected second electrodes thereof; comparing said sensed current level to a reference level by means coupled to respective third electrodes of said first and second switching means, said reference level corresponding to a current level just less than the primary current required for transformer saturation; alternately deactivating and activating said first and second switching means each time said current level is substantially equal to said reference level wherein transformer saturation is prevented; and inductively loading a secondary winding of said transformer for providing a generally linear ramp shaped increasing waveform to said current through said first and second switch means throughout the conduction thereof, respectively, until said reference level is reached.
Claim 9
Dependent Claim
20 words
The method of claim 6 wherein said step of alternately switching is carried out by means of push-pull connected transistors.
Claim 10
Dependent Claim
19 words
The method of claim 6 wherein said step of sensing is carried out by means of a sampling resistor.
Claim 11
Dependent Claim
18 words
The method of claim 6 wherein said step of comparing is carried out by means of a transistor.
Claim 12
Dependent Claim
228 words
A one-transformer DC to DC converter comprising: a transformer having primary and secondary windings and a feedback winding; first and second switching means coupled to said feedback winding for providing an oscillator by alternately switching a current, in response to signals from said feedback winding, through a primary winding of said transformer which is connected to like first electrodes of said first and second switching means; means connected to common connected second electrodes of said first and second switching means for sensing a level of said current therethrough; means coupled to respective third electrodes of said first and second switching means for comparing said sensed current level to a predetermined reference level, said reference level corresponding to a current level just less than the primary current required for transformer saturation, and alternately deactivating and activating said first and second switching means each time said current level is substantially equal to said reference level wherein transformer saturation is prevented; means connected to a secondary winding of said transformer for converting a variable polarity voltage signal induced thereat by current in said primary winding to a constant polarity voltage; and means coupled to said converting means for inductively loading said transformer to impart a generally ramp shaped increasing waveform to said current through said first and second switching means throughout the conduction time thereof until said reference level is reached.
Claim 13
Dependent Claim
228 words
A one-transformer DC to DC converter comprising: a transformer having primary and secondary windings and a feedback winding; first and second switching means coupled to said feedback winding for providing an oscillator by alternately switching a current, in response to signals from said feedback winding, through a primary winding of said transformer which is connected to like first electrodes of said first and second switching means; means connected to common connected second electrodes of said first and second switching means for sensing a level of said current therethrough; means coupled to respective third electrodes of said first and second switching means for comparing said sensed current level to a predetermined reference level, said reference level corresponding to a current level just less than the primary current required for transformer saturation, and alternately deactivating and activating said first and second switching means each time said current level is substantially equal to said reference level wherein transformer saturation is prevented; means connected to a secondary winding of said transformer for converting a variable polarity voltage signal induced thereat by current in said primary winding to a constant polarity voltage; and means coupled to said converting means for inductively loading said transformer to impart a generally ramp shaped increasing waveform to said current through said first and second switching means throughout the conduction time thereof until said reference level is reached.
Claim 14
Dependent Claim
65 words
The converter of claim 10 wherein said first and second switching means comprise transistors, and wherein said comparing means comprises a transistor having a control electrode coupled to said current sensing means and an output electrode connected to common connected first like electrodes of a pair of diodes having second like electrodes connected to said third electrodes of said first and second switching means, respectively.
Claim 15
Dependent Claim
13 words
The converter of claim 10 wherein said sensing means comprises a sampling resistor.
Claim 16
Dependent Claim
16 words
The converter of claim 10 wherein said converting means comprises a pair of series connected diodes.
Claim 17
Dependent Claim
17 words
The converter of claim 10 wherein said inductively loading means comprises a pair of series connected inductors.
Claim 18
Independent Claim
205 words
A method for controlling a one-transformer DC to DC converter comprising the steps of: alternately switching a current through a primary transformer winding by first and second switching means connected thereto at respective first electrodes thereof and having respective third electrodes thereof coupled to a feedback transformer winding forming a self oscillating transformer circuit; sensing a level of current through said first and second switching means by means connected to common connected second electrodes thereof; comparing said sensed circuit level to a predetermined reference level, said reference level corresponding to a current level just less than the primary current required for transformer saturation, by means coupled to said respective third electrodes of said first and second switching means; alternately deactivating and activating said first and second switching means each time said current level is substantially equal to said reference level wherein transformer saturation is prevented; converting a variable polarity voltage signal induced at a secondary winding of said transformer by current in said primary winding to a constant polarity voltage; and inductively loading said transformer to impart a generally linear ramp shaped increasing waveform to said current through said first and second switching means throughout the conduction time thereof until said reference level is reached.
Claim 19
Independent Claim
205 words
A method for controlling a one-transformer DC to DC converter comprising the steps of: alternately switching a current through a primary transformer winding by first and second switching means connected thereto at respective first electrodes thereof and having respective third electrodes thereof coupled to a feedback transformer winding forming a self oscillating transformer circuit; sensing a level of current through said first and second switching means by means connected to common connected second electrodes thereof; comparing said sensed circuit level to a predetermined reference level, said reference level corresponding to a current level just less than the primary current required for transformer saturation, by means coupled to said respective third electrodes of said first and second switching means; alternately deactivating and activating said first and second switching means each time said current level is substantially equal to said reference level wherein transformer saturation is prevented; converting a variable polarity voltage signal induced at a secondary winding of said transformer by current in said primary winding to a constant polarity voltage; and inductively loading said transformer to impart a generally linear ramp shaped increasing waveform to said current through said first and second switching means throughout the conduction time thereof until said reference level is reached.
Claim 20
Dependent Claim
20 words
The method of claim 15 wherein said steps of alternately switching and comparing are carried out by means of transistors.
Claim 21
Dependent Claim
19 words
The method of claim 15 wherein said step of sensing is carried out by means of a sampling resistor.
Claim 22
Dependent Claim
22 words
The method of claim 15 wherein said step of converting is carried out by means of a pair of series connected diodes.
Claim 23
Dependent Claim
23 words
The method of claim 15 wherein said step of inductively loading is carried out by means of a pair of series connected inductors.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-20 | 1988-11-19 | 1989-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-20 | 1992-11-19 | 1993-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-20 | 1996-11-19 | 1997-05-21 | $7700.00 | Window Closed / Lapsed |